DENVER & RIO GRANDE WESTERN ROUTE, 



65 



out following closely the rocks outcropping in the cliffs. Thus, a 

 short distance west of the station at Pueblo the traveler may notice 

 on the south (left) that the cliffs are composed of a dark shale, which 

 is the bottom bed of the Pierre shale, of Cretaceous age. A little 

 farther along a chalky rock rises from below the river, and the dark 

 shale can be seen only in the upper part of the cliff, and within a 

 short distance it disappears altogether. The chalky rock is the Xio- 

 brara, which in many places consists largely of limestone but here 

 consists mosth'^ of calcareous shale and thin beds of limestone having 

 a total thickness of 600 or TOO feet. Farther west the Niobrara also 

 rises to the tops of the cliffs, and near milepost 122, it gives place to 

 the Carlile shale, which is about 210 feet thick. Half a mile farther 

 on this shale is replaced by a bed of massive limestone (Greenhorn), 

 which like the others rises gradually westward in a great fold, de- 

 scribed below. Below the Greenhorn limestone lies the Graneros 

 shale, which in its upper part contains considerable sandstone in thin 

 layers. This formation is 200 feet thick. 



The fold in these beds, which is here cut directly through by 

 Arkansas River, has lifted them into a broad, flat dome. The center 

 of this dome is marked by a thick bed of sandstone (Dakota) , which 

 is just brought to the surface near milepost 126 but which the 

 river has not yet succeeded in cutting through. The rocks dip 

 slightly in all directions from this central part. If the traveler has 

 been following the formations from Pueblo he has seen at least 1,200 

 feet of rocks rise from below river level. Originally these rocks may 

 have formed a large hill at this place, but the river has kept them 

 washed away possibly as fast as they rose, and to-day, except for the 

 dip of the rocks, there is no evidence on the surface of such a dome. 



From the center of the dome near milepost 126 the beds dip up 

 the river in the direction in which the train is moving, and they 

 disappear beneath the river in reverse order from that in which they 

 appeared on the east. At Livesey siding the Greenhorn limestone 

 has reached water level. It soqn disappears, and then the beds lie 

 nearly flat for a long distance. 



All the rocks thus far exposed along Arkansas River except the 

 Dakota contain marine shells, which indicate that they were laid 



lawmakinsr the last .Tefferson legis- 

 lature passed away. According to 

 a statement in Smiley's History of 

 Denver, 



"Jefferson Territory made its last 

 gasp in June, 1861. On the sixth day 

 of that month Gov. Steele issued from 

 Denver a proclamation announcing the 

 arrival of Gov. Gilpin and the insti- 

 tution of the Government of the Terri- 



tory of Colorado under the act of 

 Congress signed by President Bu- 

 chanan February 28, 1861. * * * 

 Thus ended the most interesting and 

 picturesque endeavor of an isolated 

 community to establish and maintain 

 within itself a government of and by 

 law that the student of self-govern- 

 ment will find in the history of this 

 country." 



